Micro-electromechanical systems (MEMS) are used in a variety of applications, including optical display systems. Such systems often include a light source that projects light rays onto a light modulator panel. In many optical display systems, the light modulator panel includes an array of MEMS devices commonly referred to as pixels. The pixels modulate light to control its color, intensity, hue, or other characteristics.
For example, some pixels include reflective plates that are selectively tilted to direct light along a desired path. More specifically, when such pixels are in an ON state, the reflective plate is tilted such that the pixels direct light incident thereon to the display optics, which focus the light onto a display surface. Similarly, when such pixels are in an OFF state, the reflective plate is oriented such that the light is directed away from the display surface. By controlling the frequency with which the light is directed from each pixel to the display surface, each pixel is able to produce an output that varies from light to dark on the display surface. By properly controlling an array of pixels, a full image may be formed.
Optical Modulators that are based on tilting mirrors may be limited in their capability to use light by the magnitude of the angle of mirror tilt. In particular, in order to maintain a high extinction ratio on the screen, it may be desirable to increase the separation of the display and non-display light. As a result, if the mirror tilt angle is θ and the area of a pixel is A, the light that can be processed by a single pixel is proportional to A*sin2(θ). For N pixels in an optical modulator the useable light is proportional to N*A*sin2(θ). If the mirror tilt angle is small or is reduced, it may be desirable to increase the area of the modulator. Typical projection assemblies are often configured to cover a modulator with a diagonal dimension of less than about 0.9 inches.